Senjiro Shiba is a prominent scientist and archaeologist whose discovery of a Yamatai Kingdom bronze bell revealed its link to dormant Queen Himika and her advanced technology. This led to his targeted assassination by her forces. Before death, Senjiro used the bell’s power to save his mortally wounded son Hiroshi by transforming him into a cyborg capable of merging with robotic components to form the combat unit Jeeg. Simultaneously, Senjiro preserved his consciousness through a brain upload into the Build Base’s computer system, enabling posthumous tactical and scientific guidance. This digital entity later executed a self-sacrificial attack against the enemy fortress Orochi.

In the 2007 sequel *Kotetsushin Jeeg*, Senjiro survived the initial Yamatai conflict, escaping Kyushu before a dimensional barrier sealed it. Utilizing a second bronze bell, he developed a new Jeeg unit. Fifty years later, he established a new Build Base overlooking the sealed zone as chief scientist, preparing defenses against Himika’s resurgence. He mentored new pilot Kenji Kusanagi while coordinating with former allies like Miwa Uzuki (now Miwa Tamashiro) and the Build Angels squadron. His expertise remained central to countering threats, including adapting Jeeg’s modular systems for new combat scenarios.

Across both timelines, Senjiro operates as an omnidisciplinary researcher spanning archaeology, robotics, and applied ancient technology. His actions consistently leverage the bronze bell’s capabilities to protect humanity from existential threats. The sequel highlights his direct strategic and technological involvement, contrasting with his original sacrificial role.